Digital holographic imaging apparatuses are known as disclosed in, tier example, in Patent Literatures (PTLs) 1 to 3. PTL 1 discloses a digital holographic imaging apparatus, which uses a half mirror to spatially separate light emitted from a light source into reference light and object illumination light, and uses the half mirror to have the reference light interfere with light reflected by an object irradiated with the object illumination light, to thereby generate an interference pattern, which is captured by an image sensor.
PTLs 2 and 3 disclose a digital holographic imaging apparatus, which irradiates light radiated from a light source onto a reflecting surface and an object, which are disposed in a substantially common optical path, and causes light reflected by the reflecting surface (reference light) to interfere with light reflected by the object (objet light), to thereby generate an interference pattern, which is captured by an image sensor.